package qmc

func newStaticCipher() *staticCipher {
	return &defaultStaticCipher
}

var defaultStaticCipher = staticCipher{}

type staticCipher struct{}

func (c *staticCipher) Decrypt(buf []byte, offset int) {
	for i := 0; i < len(buf); i++ {
		buf[i] ^= c.getMask(offset + i)
	}
}
func (c *staticCipher) getMask(offset int) byte {
	if offset > 0x7FFF {
		offset %= 0x7FFF
	}
	idx := (offset*offset + 27) & 0xff
	return staticCipherBox[idx]
}

var staticCipherBox = [...]byte{
	0x77, 0x48, 0x32, 0x73, 0xDE, 0xF2, 0xC0, 0xC8, //0x00
	0x95, 0xEC, 0x30, 0xB2, 0x51, 0xC3, 0xE1, 0xA0, //0x08
	0x9E, 0xE6, 0x9D, 0xCF, 0xFA, 0x7F, 0x14, 0xD1, //0x10
	0xCE, 0xB8, 0xDC, 0xC3, 0x4A, 0x67, 0x93, 0xD6, //0x18
	0x28, 0xC2, 0x91, 0x70, 0xCA, 0x8D, 0xA2, 0xA4, //0x20
	0xF0, 0x08, 0x61, 0x90, 0x7E, 0x6F, 0xA2, 0xE0, //0x28
	0xEB, 0xAE, 0x3E, 0xB6, 0x67, 0xC7, 0x92, 0xF4, //0x30
	0x91, 0xB5, 0xF6, 0x6C, 0x5E, 0x84, 0x40, 0xF7, //0x38
	0xF3, 0x1B, 0x02, 0x7F, 0xD5, 0xAB, 0x41, 0x89, //0x40
	0x28, 0xF4, 0x25, 0xCC, 0x52, 0x11, 0xAD, 0x43, //0x48
	0x68, 0xA6, 0x41, 0x8B, 0x84, 0xB5, 0xFF, 0x2C, //0x50
	0x92, 0x4A, 0x26, 0xD8, 0x47, 0x6A, 0x7C, 0x95, //0x58
	0x61, 0xCC, 0xE6, 0xCB, 0xBB, 0x3F, 0x47, 0x58, //0x60
	0x89, 0x75, 0xC3, 0x75, 0xA1, 0xD9, 0xAF, 0xCC, //0x68
	0x08, 0x73, 0x17, 0xDC, 0xAA, 0x9A, 0xA2, 0x16, //0x70
	0x41, 0xD8, 0xA2, 0x06, 0xC6, 0x8B, 0xFC, 0x66, //0x78
	0x34, 0x9F, 0xCF, 0x18, 0x23, 0xA0, 0x0A, 0x74, //0x80
	0xE7, 0x2B, 0x27, 0x70, 0x92, 0xE9, 0xAF, 0x37, //0x88
	0xE6, 0x8C, 0xA7, 0xBC, 0x62, 0x65, 0x9C, 0xC2, //0x90
	0x08, 0xC9, 0x88, 0xB3, 0xF3, 0x43, 0xAC, 0x74, //0x98
	0x2C, 0x0F, 0xD4, 0xAF, 0xA1, 0xC3, 0x01, 0x64, //0xA0
	0x95, 0x4E, 0x48, 0x9F, 0xF4, 0x35, 0x78, 0x95, //0xA8
	0x7A, 0x39, 0xD6, 0x6A, 0xA0, 0x6D, 0x40, 0xE8, //0xB0
	0x4F, 0xA8, 0xEF, 0x11, 0x1D, 0xF3, 0x1B, 0x3F, //0xB8
	0x3F, 0x07, 0xDD, 0x6F, 0x5B, 0x19, 0x30, 0x19, //0xC0
	0xFB, 0xEF, 0x0E, 0x37, 0xF0, 0x0E, 0xCD, 0x16, //0xC8
	0x49, 0xFE, 0x53, 0x47, 0x13, 0x1A, 0xBD, 0xA4, //0xD0
	0xF1, 0x40, 0x19, 0x60, 0x0E, 0xED, 0x68, 0x09, //0xD8
	0x06, 0x5F, 0x4D, 0xCF, 0x3D, 0x1A, 0xFE, 0x20, //0xE0
	0x77, 0xE4, 0xD9, 0xDA, 0xF9, 0xA4, 0x2B, 0x76, //0xE8
	0x1C, 0x71, 0xDB, 0x00, 0xBC, 0xFD, 0x0C, 0x6C, //0xF0
	0xA5, 0x47, 0xF7, 0xF6, 0x00, 0x79, 0x4A, 0x11, //0xF8
}
